1. Field of the Invention
The present invention relates to a rope or wire gripping device for releasably gripping a rope, a wire, or a similar elongated flexible member, said device comprising a frame and a pair of spaced rope engaging members or jaw members, which have a pair of oppositely arranged, generally parallelly extending rope engaging surfaces defining therebetween a passageway for said rope or wire, and which are mounted in said frame so as to be movable in relation to each other and so that a force applied to said rope engaging surfaces and acting in one direction of said rope passageway will tend to move the rope engaging members closer to each other towards a locking position, while a force applied to the rope engaging surfaces and acting in the opposite direction of the rope passageway will tend to increase the spacing of the rope engaging surfaces and to move the rope engaging members towards a releasing position.
Such gripping devices may, for example, be used on sailing ships and in other places, where it is desirable to releasably grip and hold a tensioned rope or wire. As an example, the gripping device of the above type may be used in connection with winches, tackles, and other rope pulling devices, which may, for example, be used for hauling in sails.
2. Description of Prior Art
One type of known rope gripping devices comprises a rope engaging member in the form of an eccentric with an operating handle, by means of which the eccentric may be swung between a rope engaging position in which the rope or wire is pinched between the eccentric and an oppositely arranged rope engaging surface, and a rope releasing position, in which the eccentric has been moved out of engagement with the rope or wire. When a gripping device of this known type is used for gripping and holding a highly tensioned rope or wire, the rope engaging surface defined by the eccentric must be pressed against the rope at a correspondingly high compressive force. As the convexly curved rope engaging surface of the eccentric which is normally serrated comes into engagement with a rather small area of the rope surface only, the specific pressure may be extremely high. Consequently, the rope or wire is exposed to heavy wear, and this is rather undesirable in view of the fact that quite often it is the same part of the rope or wire which is repeatedly brought into engagement with the rope engaging member or excentric.
U.S. Pat. No. 3,824,653 discloses a rope gripping or locking device of the above type and comprising oppositely arranged, parallelly extending rope engaging surfaces for releasably gripping and locking a rope or wire positioned therebetween. The rope engaging surfaces of this known device are defined on a wedge-shaped jaw member displaceably arranged in the frame of the device, and by a second jaw member mounted on the frame by means of parallel, swingable arms. In the known gripping device, the mutual distance between the rope engaging surfaces may be adapted to the thickness or diameter of the rope or wire by displacing the wedge-shaped jaw member in relation to the frame of the device. Otherwise, the wedge-shaped jaw member is fixed in relation to the frame during use of the gripping device. When a rope or wire is gripped or locked in the known gripping device by parallel displacing of the said second jaw member in relation to the fixed wedge-shaped jaw member the movement of the second jaw member has not only a component directed transversely to and towards the wedge-shaped jaw member, but also a component in a direction parallel to the longitudinal direction of the rope or wire. The components extending in the longitudinal direction of the rope ensures that a tensile force applied to the rope in the said direction will cause the rope engaging surfaces to be forced towards each other, whereby an advantageous self-locking effect is obtained. However, the said component of movement of the movable jaw member in the longitudinal direction of the rope in relation to the stationary wedge-shaped jaw member causes undesired wear of the wire or rope.
Other known rope or wire gripping devices (known for example from the European patent application published under No. 64,571, U.S. Pat. No. 3,886,631, French Pat. No. 1,489,029, and Swedish Pat. No. 18,665) comprise rope engaging members or jaw members, which may be pressed towards each other and directed into engagement with the rope or wire without any substantial component of movement in the longitudinal direction of the rope. However, these known gripping devices do not have the above mentioned desirable self-locking effect in response to tensile forces applied to the rope.